(DOCSP-30183) Add info about migrating to multi-clusters (#1356)

* (DOCSP-30183) Add info about migrating to multi-clusters

* Edits

Author: JuliaMongo

source/includes/facts/fact-migrating-to-multi-clusters.rst

@@ -0,0 +1,5 @@
+You can create a new |multi-cluster| and contact
+`MongoDB Support <https://support.mongodb.com/welcome>`__ to help you
+migrate data from your existing |k8s| deployment to a |multi-cluster|.
+You can't extend an existing single-Kubernetes cluster deployment to
+new |k8s| clusters.

source/multi-cluster-arch.txt

@@ -25,8 +25,7 @@ The following limitations exist for |multi-clusters|:
 
 - Deploy only replica sets. Sharded cluster deployments aren't supported.
 - Use |onprem| versions later than 5.0.7.
-- 
-  Deploy |onprem| on a single cluster, and if deploying in |k8s|, deploy |onprem|
+- Deploy |onprem| on a single cluster, and if deploying in |k8s|, deploy |onprem|
   on a central cluster. To learn more, see :ref:`om_with_multi-clusters`.
 
   .. important::
@@ -51,6 +50,8 @@ The following limitations exist for |multi-clusters|:
 - Don't add a :github:`ServiceMonitor</prometheus-operator/prometheus-operator/blob/main/Documentation/user-guides/getting-started.md#related-resources>`
   to your |mongodb-multis|. The |k8s-op-short| doesn't support integration with Prometheus.
 
+- .. include:: /includes/facts/fact-migrating-to-multi-clusters.rst
+
 .. _multi-cluster-capabilities:
 
 Multi-Kubernetes-Cluster Deployment Capabilities

source/multi-cluster-overview.txt

@@ -61,3 +61,8 @@ To learn more, see :ref:`multi-cluster-arch-ref`.
    tested these deployments with |istio|, but any service mesh that provides |fqdn|
    hostname resolution between Pods across clusters should work. To learn more,
    see :ref:`Plan for External Connectivity <mc_plan_external_connectivity>`.
+
+Migrating to Multi-Kubernetes-Cluster Deployments
+--------------------------------------------------
+
+.. include:: /includes/facts/fact-migrating-to-multi-clusters.rst